KIAA0090 is a human gene coding for a protein of unknown function. KIAA0090 has two aliases OTTHUMP00000002581 and RP1-43E13.1. The gene codes for multiple transcript variants which can localize to different subcellular compartments. KIAA0090 interacts with multiple effector proteins. KIAA0090 contains a conserved COG1520 WD40 like repeat domain thought to be the method of such interaction. Characterization of the KIAA0090 gene and its transcript products KIAA0090 is located on chromosome one in the p arm at location 1p36.132. It covers 36.74 kb, from base pairs 19451486 to 19414744. The gene is composed of 37 gt-at introns/alternative introns with 57 exons expressed in 1 unspliced form of 4253 bp and 20 alternatively spliced forms of varying lengths. The gene has 8 probable promoters. The gene is flanked by UBR4 on its right and MRTO4 on its left. This Information is graphically displayed in Figure 1. Expressed Sequence Tags and isolated cDNA clones indicate KIAA0090 is expressed ubiquitously in low to moderate levels throughout the body. This includes but is not limited to testis, tongue, lung, cerebellum, brain, mammary gland, trachea, placenta, esophageal, salivary gland, brain, hippocampus, amygdale, bone marrow, thalamus, spleen, uterus, thymus, kidney, eye, heart, gall bladder, prostate, liver, parathyroid gland, ovary, stomach, skeletal muscle, colon, pancreas, and skin. Expression of KIAA0090 changes throughout development (embryogenesis, fetal, adult, etc.)and during carcinogenesis. Evidence indicates a correlation between conditions and expression level but no data exists to suggest KIAA0090 is responsible for any disease or stage of development. The mRNA for this gene codes for 18 protein isoforms6. The remaining 3 splice variants have no evidence supporting their ability to be translated. Characterization of the KIAA0090 Protein Product Analysis indicates the KIAA0090 unspliced protein product to be 993 amino acids long with an isoelectric point of 7.418 and a molecular weight of 111765.73 Daltons. The primary structure of this protein contains 4 conserved domains. This includes a signal peptide from position 1 to 22, a COG1520 WD40 like domain, a leucine zipper domain, a DUF1620 domain (domain of unknown function), and a transmembrane domain. These can be viewed in Figure 2. Several conserved cysteine residues are present at positions 226,235, 335, 364,449, 581, 675, 925, and 985. Several internal localization signals are also present. Dependent on splice outcome and posttranslational modification, these additional signals indicate the protein could localize to the peroxisome, the plasma membrane, outside the cell, the cytosol, the nucleus,